1. Field of the Invention
This invention relates to an IC protective device in a memory card operating electronic apparatus in which a memory card is inserted into an electronic apparatus such as a computer, word processor, and the like.
2. Related Art
A memory card 1 is a card for inputting data to an electronic apparatus when inserted therein. The card 1 comprises, as shown in FIGS. 1A and 1B, a card body 2 composed of a planar insulative plate and having an IC 3 as a memory element. As shown in FIG. 2A, the memory card 1 is inserted into a card receiving slot of the electronic apparatus so that electrode pads 4a, 4b of the IC 3, arranged in such a manner to expose themselves on a surface of the memory card 1, are brought into contact with contacts 5a, 5b, arranged within the electronic apparatus, so that the memory card 1 is electrically connected to an electronic circuit (wiring circuit board 7) within the electronic apparatus. By doing so, the IC card 1 renders a new memory function to the electronic apparatus through the IC memory element.
In the memory card 1, it is necessary to effectively arrange a plurality of electrode pads 4a, 4b on the surface of the memory card 1 having a limited area. Therefore, it is necessary for such a memory card 1 that the electrode pads are arranged side by side in a parallel relation not only in a short direction of the card 1 (i.e., perpendicular direction to a direction of insertion of the card 1) but also in a long direction of the card 1(direction of insertion of the card 1).
On the other hand, as shown in FIG. 2A, the contacts 5a, 5b, which are designed to come in contact with the electrode pads 4a, 4b, are also arranged such that contact points 6a, 6b disposed on distal ends of the contacts 5a, 5b are offset in the direction of insertion of the card 1, so that when the card insertion is completed, the contact points 6a, 6b are in contact with the electrode pads 4a in the front row and the electrode pads 4b in the rear row.
In the above memory card operating electronic apparatus, it occurs that, as shown in FIG. 2B, during a process for inserting and withdrawing the memory card 1 to and from the electronic apparatus, the contact points 6b of the contacts 5b in the rear row, which are arranged to contact the electrode pads 4b in the rear row on the IC card 1, are slidingly passed on surfaces of the electrode pads 4a in the front row which the contact points 6a of the contacts 5a in the front row are intended to contact.
That, is, during a process for inserting and withdrawing the memory card 1 to and from the electronic apparatus, it occurs that both the contact points 6a, 6b of the contacts 5a, 5b in the front and rear rows are slidingly passed on the surfaces of the electrode pads 4a in the front row simultaneously. This occurrence brings about the problem of damaging the IC due to the electrical charge, which is stored in the charged part 9 within the electronic circuit while the charged part 9 is in use, incurred to the IC within the electronic apparatus or IC within the memory card 1 formed on the wiring circuit board 7 through the contacts 5a, 5b which are designed to contact the electrode pads 4a in the front row, especially during a process for withdrawing the memory card 1 from the electronic apparatus. The memory card 1 is repeatedly inserted and withdrawn in use. Therefore, each time the memory card 1 is inserted in and withdrawn from the electronic apparatus, the charge stored in the charged part 9 is incurred to the IC. This increases the chances of damaging to the IC.
FIGS. 2A and 2B show a control circuit 8, which is to be contacted with the IC 3 within the memory card 1 through the contacts 5a, 5b and electrode pads 4a, 4b, respectively. This control circuit 8 is a circuit having the functions of providing data held by the IC 3 within the memory card 1 to a data processing circuit within the apparatus or recording the data of the data processing circuit within the apparatus on the IC 3 within the memory card 1.
The present invention has been accomplished in view of the above.